The present invention relates to a general blood analyzing system and more particularly to an integrated general blood analyzing system that comprises a sample (sample)-rack transportation system, blood analyzers, and an automatic smearing device.
Blood analyzers which take blood samples from a sample container and then classify and count blood corpuscles are well known, as are devices that make a smear sample by smearing the blood sample on a slide glass.
Japanese Patent Laid-open Publication No. 63-217273 discloses a system that combines more than one blood analyzer for the performance of a variety of tests with a transportation device for an array of blood samples in sample containers. However, this system does not include the preparation of blood smears for further examination, requiring that the blood smears be made by hand or that the samples be transferred to other devices for the preparation of smears.
Automatic smearing devices for preparing blood smears on slides are also well known. Japanese Examined Patent Publications No. 61-45769, No. 62-16380, and Japanese Patent Laid-open Publication No. 57-171259 disclose automatic apparatus for preparing blood smears. Publication No. 61-45769, describes an apparatus, wherein at least one of a moving velocity and an angle of a pulled glass is varied continuously as it is drawn over a blood specimen in order to make the thickness of a sample blood smear constant. Publication No. 62-16380 describes an apparatus wherein the rotating speed of a motor is controlled in order to disperse blood corpuscles evenly on a slide glass. Publication No. 57-171259 describes an apparatus wherein the angle of a pulled glass decreases gradually as it is drawn over a blood specimen so as to minimize the changes in smear thickness.
In the spinner method, a drop of blood is placed on the surface of a glass slide, which then is spun so that the blood is spread over the surface and smeared by centrifugal force. The wedge method, on the other hand, is a method in which a glass slide is drawn through a blood sample along its long side to smear blood on its surface.
However, these methods do not provide consistency between smear samples because they do not adjust for variations in specific character between blood samples.
A smeared sample rack is provided into which smeared slides are placed. The smeared samples are then dipped in a dyeing liquid along with the smeared sample rack.
The smeared sample rack needs a handle with which it can be carried or dipped into a dyeing liquid. When the rack is held by its handle, the handle must be centered. However, in an automatic loading device the rack handle must be movable so as not to interfere with loading of the rack. In addition, the handle must always take the same position each time the rack is loaded to facilitate the handling of loaded racks. Conventional racks do not meet these requirements.
For quality analysis, the thickness of prepared blood smears must be consistent from smear to smear, regardless of the great variety of possible blood consistencies.
Japanese Examined Patent Publication No. 61-45769 discloses a method to achieve the required consistency in which at least one of the angle or the velocity of a smearing glass is changed continuously. However, this device cannot automatically determine the consistency of the blood to be smeared and must be adjusted for separate blood samples.
Separate devices for measuring blood viscosity are well known. For example, a method is known that determines blood viscosity by measuring its flow time through a measured length of capillary tubing. It is not clear how these conventional devices could be installed in an automatic smearing device. If such a blood viscosity measuring device were integrated into an automatic smearing device, the device would be complex, large, slow and costly.
Although an automatic smearing device employs automated smearing preparation processes, various monitoring functions are required. Detection of the presence of a smear is an example. If there is no blood smear on a slide to be examined because of a machine malfunction, a warning must be issued.
A conventional method for detecting a blood smear focuses a known intensity light through a smeared slide and measures the intensity of the light transmitted by the slide. The light loss through a blood smeared slide is greater than that through a clean slide. However, because of the variety of smears produced, a very thin smear might not be detected.
Conventional methods for printing an identifier on a blood smeared slide include a printer disclosed in Japanese Patent Laid-open Publication No. 55-48655 that uses a printing plate and ink.
The major problem presented by the use of a printing plate and ink is that because the smeared specimen is dyed following blood sample smearing and the dyeing liquid contains alcohol, identifying marks imprinted in ink may wash off during the dyeing process.
Another approach is to imprint the identifier with a thermal printer on a resin-coated portion of a slide. This method requires that expensive, specially prepared slides be used for preparing smeared blood samples.
The use of a dot matrix impact printer for imprinting identifiers on slides is also well know. Dot matrix impact printers print using a printer head that strikes an ink ribbon with pins of a printer head to leave ink dots on the slide being identified.
Problems that limit the effectiveness of conventional dot matrix impact printers include the breaking of slides as they are impacted by printer head pins and the short life of the printer head pins when used in this application.
Another major problem of conventional dot matrix impact printers is that they do not provide good penetration of ink into the hollows of the ground glass portion of the slides on which the printing is done. This allows the ink identifier to be washed away during dyeing.